1. Field of Invention
The invention relates to vehicle control apparatus and methods for controlling the rotating and stopping of a drive power source based on a predetermined condition.
2. Description of Related Art
Known vehicle control apparatus stop an engine regardless of operation of an ignition key if a stop condition is met, for the purposes of improving fuel economy, reducing emission gasses, reducing noise, etc. An example of such an apparatus is described in Japanese Patent Application Laid-Open No. 9-310639. A vehicle control apparatus described in that publication is designed for vehicles in which a hydraulically controlled or electrically controlled torque converter is connected to an output side of an engine. Examples of the condition for stopping the engine include the actuation of a parking brake, the duration of a stop of the vehicle based on an event that a door is opened by a passenger, and the like. Examples of the condition for starting the engine include the release of the parking brake, the closing of a door accomplished by a passenger, and the like.
In the vehicle control apparatus described in the aforementioned publication, however, even when the condition for stopping the engine is met during a stop of the vehicle, it is not preferable that the engine is be stopped if another condition is met, for example, if there is a request to actuate an air-conditioner compressor that is driven by power from the engine. The torque converter is an apparatus that transfers power between a driving-side rotating member and a driven-side rotating member based on kinetic energy of a fluid. The driven-side rotating member of the torque converter remains stopped during a stopped state of the vehicle. Therefore, if the engine cannot be stopped even though the engine stopping condition is met, a state in which the driving-side rotating member and the driven-side rotating member turn relative to each other is maintained. Therefore, the fluid in the torque converter is agitated, so that a generally-termed dragging torque occurs. As a result, the engine load increases, and the fuel consumption increases.
It is an object of the invention to curb the increase in the load on a drive power source if the drive power source cannot be stopped despite output of a request to stop the drive power source.
A first aspect of the invention relates to a vehicle control apparatus which includes a driven device that is driven by power from a drive power source, a system that controls rotating and stopping of the drive power source based on a predetermined condition, a detector that detects a request to stop the drive power source, and a controller that determines that the system is in a state where the system is not allowed to stop the drive power source, and that controls the driven device so as to reduce a load on the drive power source. The controller controls the driven device so as to reduce the load on the drive power source, if the detector detects the request to stop the drive power source and the controller determines that the system is in the state where the system is not allowed to stop the drive power source.
According to the first aspect of the invention, if the system is in the state that is not appropriate for execution of the control of stopping the drive power source despite output of the request to stop the drive power source, the driven device is controlled so as to reduce the load on the drive power source.
A second aspect of the invention relates to a vehicle control method for a vehicle having a drive power source and a driven device that is driven by power transferred from the drive power source. This control method includes a step of detecting a request to stop the drive power source, a step of determining that a system is in a state where the drive power source is not allowed to be stopped, and a step of controlling the driven device so as to reduce a load on the drive power source if the request to stop the drive power source is detected and it is determined that the system is in the state where the drive power source is not allowed to be stopped.
According to the second aspect of the invention, if the system is in the state that is not appropriate for execution of the control of stopping the drive power source despite output of the request to stop the drive power source, the driven device is controlled so as to reduce the load on the drive power source.
A third aspect of the invention relates to a vehicle control apparatus which includes a driven device that is driven by power from a drive power source, a system that controls rotating and stopping of the drive power source based on a predetermined condition, a detector that detects a request to stop the drive power source, and a controller that determines that the system is in a state where the system is allowed to stop the drive power source, and that controls the driven device so as to reduce a load on the drive power source. The controller controls the driven device so as to reduce the load on the drive power source, if the detector detects the request to stop the drive power source and the controller determines that the system is not in the state where the system is allowed to stop the drive power source.
A fourth aspect of the invention relates to a vehicle control method for a vehicle having a drive power source and a driven device that is driven by power transferred from the drive power source. This control method includes a step of detecting a request to stop the drive power source, a step of determining that a system is in a state where the drive power source is allowed to be stopped, and a step of controlling the driven device so as to reduce a load on the drive power source if the request to stop the drive power source is detected and it is determined that the system is not in the state where the drive power source is allowed to be stopped.